Weight loss help please

So I have fibromyalgia and under active thyroid which makes it harder for me to lose weight. When I try and exercise I am in pain and get tired really quickly, (never been like it before). As I have put on loads of weight I have now got low self esteem and depression.... does anyone else suffer with the same? Any exercise tips? I don't eat badly at all... and I try and exercise but the following day I am in agony and cannot walk proper...

Please don't fat shame me in my picture as I am already depressed about my size enough! I used to fit into size 8,10 and 12 clothes. I am now a size 14-16 and I hate it!

I have inserted a picture of me and of the size I would be happy and comfortable with...

Update:

I eat as healthy as I can, eating fruits and veg everyday, don't drink pop or anything else other than water.. I take a load of tablets a day but the pain is the same... I also try walking but my legs cramp up if i walk to far or too fast... I tried using the step aerobics on my wii fit, done 5,600 steps and the following day I could not walk at all...,

I'm on 4 gabapentin a day for my fibromyalgia

A levothyroxine tablet for my thyroid a day

A depressant tablet a day

And then I take paracetamols, naproxen and lanzoprazolen for pain.

Plus my vitamins and folic acid as trying for a baby.

Update:

For the lady saying eat less... I hardly eat in a day! I eat 1 proper meal with my fiancé which is sweet potatoes and a chicken breast with peas. I have a small rice pot yoghurt twice a day , about 10 bottles of water a day, wang me send you a picture if what I eat a day?? I gladly will as I don't eat bad!